Entwicklung und Aufbau einer neuartigen MOCVD-Anlage zum Wachstum ferroelektrischer Dünnschichten

Schäfer, Patrick Ralf

Dissertation / PhD Thesis/Book

Entwicklung und Aufbau einer neuartigen MOCVD-Anlage zum Wachstum ferroelektrischer Dünnschichten

Schäfer, P. R. (Corresponding author)FZJ*

2002
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich

Jülich : Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag, Berichte des Forschungszentrums Jülich 3956, 133 p. (2002) = Aachen, Techn. Hochsch., Diss., 2002

Please use a persistent id in citations: http://hdl.handle.net/2128/176

Report No.: Juel-3956

Abstract: Oxide ceramic thin films with a high permittivity or ferroelectric properties are currently investigated worldwide regarding their application in highly integrated dynamic solid state memories (DRAMs) or non-volatile ferroelectric memories (FeRAMs). The integration of electroceramic materials into the CMOS silicon technology requires a manufacturing process capable of depositiog ceramic thin films with uniform composition and structure an three-dimensional surfaces. Thereby, the underlying silicon structures must not be damaged by high process temperatures and resulting diffusion processes. These requirements can be fulfilled by the "metal-organic chemical vapor deposition" (MOCVD) that is considered the most promising method for the growth of ceramic thin films with respect to industrial use. This thesis deals with the production of ferroelectric thin films using the MOCVD technology. The main focus is put an the design and construction of a complete MOCVD research system that is equipped with a novel non-contact vaporizer System. The precursors are nebulized in an ultrasonic atomizer and injected into a hot gas stream, so they can vaporize without getting into contact with a hot surface. Hence, one of the biggest disadvantages of conventional vaporizer concepts, the contamination of the vaporizing element with decomposing chemicals, could be avoided completely, resulting in a nearly maintenance-free System. In a direct comparison with the well-established $\textit{Direct Liquid Injection Subsystem DLI-25C}$ from MKS Instruments, the advantages of non-contact evaporation were clearly demonstrated. Additionally, the scope of this work included the development of Standard deposition processes for the ternary oxides SrTiO$_{3}$, BaTiO$_{3}$ und PbTiO$_{3}$ and growth studies were performed. Electrical measurements performed on MIM structures with Pt electrodes and SrTiO$_{3}$ as dielectric indicate a high film quality comparable with results presented in the literature. Furthermore, for the first time the solid solution (Pb$_{x}$Ba$_{1-x}$)TiO$_{3}$ has been deposited by MOCVD. This material system is widely unknown in thin film form and it is well suited as a model system to investigate the influence of mechanical stresses an the film properties, because it represents a transition between the (as a thin film) superparaelectric barium titanate and the ferroelectric lead titanate. Through variation of the lead/barium ratio the tetragonal distortion of the lattice cell could be adjusted in a wide range.

Note: Record converted from VDB: 12.11.2012
Note: Aachen, Techn. Hochsch., Diss., 2002

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